Use inet_pton() to provide inet_aton() functionality

This is cleaner and simpler than the original compat code, and avoids
the strange issues that Nikos was reporting on his Windows 7
installation with inet_addr() not working correctly.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

compat.c

@@ -223,17 +223,7 @@ void openconnect__unsetenv(const char *name)
 #ifndef HAVE_INET_ATON
 int openconnect__inet_aton(const char *cp, struct in_addr *addr)
 {
-  addr->s_addr = inet_addr(cp);
-#if INADDR_NONE == 0xffffffff
-  if (addr->s_addr != 0xffffffff)
-	  return 1;
-  /* Is it an error, or was it really 255.255.255.255? */
-  if (!strcmp(cp, "255.255.255.255"))
-	  return 1;
-#else
-#error What is your INADDR_NONE?
-#endif
-  return 0;
+	return inet_pton(AF_INET, cp, addr);
 }
 #endif